configure: Remove --enable-all-warnings option

The option is not activelly tested and has bitrotten, to fix it
would require a lot of work and multiple fixes.  A better option
would to evaluate each option and enable the warning if it makes
sense.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

Makeconfig

@@ -857,12 +857,7 @@ host-test-program-cmd = $(host-built-program-cmd)
 endif
 
 # Extra flags to pass to GCC.
-ifeq ($(all-warnings),yes)
+gccwarn := -Wall -Wwrite-strings -Wundef
-+gccwarn := -Wall -Wwrite-strings -Wcast-qual -Wbad-function-cast -Wmissing-noreturn -Wmissing-prototypes -Wmissing-declarations -Wcomment -Wcomments -Wtrigraphs -Wsign-compare -Wfloat-equal -Wmultichar
-else
-+gccwarn := -Wall -Wwrite-strings
-endif
-+gccwarn += -Wundef
 ifeq ($(enable-werror),yes)
 +gccwarn += -Werror
 endif

config.make.in

@@ -50,7 +50,6 @@ c++-sysincludes = @CXX_SYSINCLUDES@
 c++-cstdlib-header = @CXX_CSTDLIB_HEADER@
 c++-cmath-header = @CXX_CMATH_HEADER@
 c++-bits-std_abs-h = @CXX_BITS_STD_ABS_H@
-all-warnings = @all_warnings@
 enable-werror = @enable_werror@
 
 have-z-execstack = @libc_cv_z_execstack@

configure

@@ -705,7 +705,6 @@ libc_cv_nss_crypt
 build_crypt
 memory_tagging
 enable_werror
-all_warnings
 force_install
 bindnow
 hardcoded_path_in_tests
@@ -804,7 +803,6 @@ enable_static_nss
 enable_force_install
 enable_maintainer_mode
 enable_kernel
-enable_all_warnings
 enable_werror
 enable_multi_arch
 enable_memory_tagging
@@ -1478,7 +1476,6 @@ Optional Features:
                           sometimes confusing) to the casual installer
   --enable-kernel=VERSION compile for compatibility with kernel not older than
                           VERSION
-  --enable-all-warnings   enable all useful warnings gcc can issue
   --disable-werror        do not build with -Werror
   --enable-multi-arch     enable single DSO with optimizations for multiple
                           architectures
@@ -4526,14 +4523,6 @@ else
   fi
 fi
 
-# Check whether --enable-all-warnings was given.
-if test ${enable_all_warnings+y}
-then :
-  enableval=$enable_all_warnings; all_warnings=$enableval
-fi
-
-
-
 # Check whether --enable-werror was given.
 if test ${enable_werror+y}
 then :

configure.ac

@@ -277,16 +277,6 @@ else
   fi
 fi
 
-dnl For the development we sometimes want gcc to issue even more warnings.
-dnl This is not the default since many of the extra warnings are not
-dnl appropriate.
-AC_ARG_ENABLE([all-warnings],
-	      AS_HELP_STRING([--enable-all-warnings],
-			     [enable all useful warnings gcc can issue]),
-	      [all_warnings=$enableval],
-	      [])
-AC_SUBST(all_warnings)
-
 AC_ARG_ENABLE([werror],
 	      AS_HELP_STRING([--disable-werror],
 			     [do not build with -Werror]),